This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The overall goal of this study is to investigate whether the effects of withdrawal reversal outweigh the net benefits of caffeine. In agreement with the idea of withdrawal reversal, our overall hypothesis is that the effects of caffeine on mood, behavior, and the BOLD signal will be greater during withdrawal than during a native caffeinated state.